Whisk butter, vanilla, sugar, and brown sugar together well.
Add an egg and whisk together.
Mix flour and baking powder, sift it, and fold it in with salt and chocolate.
Spread the cookie dough in a layer on top of the brownie by placing small blobs on top until it covers everything.
Bake the brookie at 175 degrees Celsius (347 degrees Fahrenheit) fan-forced oven for about 30 minutes.
The cake may seem slightly underbaked in the middle when it comes out, but it will set once it gets cold.
Sprinkle with a little flake salt.
Let the cake cool for a few hours in the fridge before cutting into beautiful pieces!
The cake is easiest to cut when it is completely cold!
Enjoy!